Particle, inspection particle, reagent and inspection kit, and detection method

Abstract

To solve the problem in which: there is a problem in redispersibility of particles in performing centrifugal sedimentation processing to redisperse particles, such as a case where the redispersion takes time and a case where the particle diameter does not become an initial particle diameter after the redispersion; especially, when chemically coupling a ligand to the surface of the particle, the particles are easily aggregated in a reactive functional group activation step, which makes redispersion more difficult and causes a problem; and therefore, to provide particles and inspection particles having improved redispersibility of particles, especially, improved redispersibility in the reactive functional group activation step.SOLUTION: A particle contains a copolymer having a structural unit represented by the formula (1) and a structural unit represented by the formula (B). When a structure obtained by removing R22 from the structural unit represented by the formula (B) is defined as B-X, the content of B-X in the particle is 5.0 mass% or more and 17.5 mass% or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to particles, test particles, reagents and test kits, and detection methods.

Background Art

[0002] In recent years, studies have been widely conducted on purifying or quantifying a target substance using test particles formed by chemically bonding a ligand having an affinity for the target substance to particles. Patent Document 1 describes particles having a core-shell structure and containing a carboxy group which is a reactive functional group, a 2,3-dihydroxypropyl group, and ethylene glycol dimethacrylate which is a hydrophilic crosslinking monomer in the shell. For particles used for such purposes, it is preferable to uniformly chemically bond an antibody or an antigen as a ligand to the particle surface to increase the aggregation rate to the target substance and improve the sensitivity. When performing chemical bonding to latex particles, in the activation step of the reactive functional groups on the outermost surface, the particles need to be purified by sedimenting the particles with a centrifuge or the like, removing the supernatant, and then redispersing the particle sediment. In order to uniformly bond the ligand substance, it is important that the particles are uniformly redispersed in this redispersion step. Patent Document 2 shows a method of controlling the surface charge by adding a surfactant or a dispersion aid when preparing particles to improve the redispersibility. However, in the method of controlling the surface charge by an additive, it becomes difficult to add an antigen (or antibody) to the particle surface, and since it may inhibit aggregation by an immune reaction, complicated and cumbersome adjustment is required depending on the type of antigen (or antibody) to be bonded. Therefore, a method for improving the redispersibility of particles is required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] According to the studies of the present inventors, in the structure of the particles described in Patent Document 1, when centrifugal sedimentation treatment is performed and redispersion is carried out, there are cases where it takes time for redispersion or the particle size does not become equal to the initial particle size after redispersion, and there are problems with redispersibility. In particular, when a ligand is chemically bonded to the particle surface, it was found that the particles tend to aggregate in the reactive functional group activation step and redispersion is more difficult. In addition, Patent Document 2 describes a method using an additive to improve redispersibility, but complicated and cumbersome adjustments may be required depending on the type of ligand to be bonded. Details of the particles are not described, and the reactive functional group activation step is not described either.

[0005] Therefore, an object of the present invention is to provide particles with improved redispersibility of particles, particularly particles and assay particles with improved redispersibility in the reactive functional group activation step.

MEANS FOR SOLVING THE PROBLEMS

[0006] The particles according to one aspect of the present invention are particles containing a copolymer having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (B), and when the structure excluding R in the structural unit represented by the formula (B) is B-X, the content of B-X in the particles is 5.0% by mass or more and 17.5% by mass or less. 22 When the structure excluding R in the structural unit represented by the formula (B) is B-X, the particles are particles in which the content of B-X in the particles is 5.0% by mass or more and 17.5% by mass or less.

CHEMICAL FORMULA

Chemical formula

[0007] Also, the particles according to one aspect of the present invention are particles obtained by a production method including a polymerization step of performing a polymerization reaction of a reaction system containing at least one of glycidyl methacrylate and glycidyl acrylate, a monomer represented by the following formula (G1), and a monomer represented by the following formula (A1). In the polymerization step, the total content of glycidyl methacrylate and glycidyl acrylate with respect to the content of the monomer represented by the following formula (A1) is 10% by mass or more and 70% by mass or less.

Chemical formula

Chemical formula

[0008] Also, the particles according to one aspect of the present invention are particles obtained by a production method including a polymerization step of performing a polymerization reaction of a reaction system containing at least one of glycidyl methacrylate and glycidyl acrylate and a monomer represented by the following formula (G1), and in the particles, the structural unit represented by the following formula (B) derived from at least one of glycidyl methacrylate and glycidyl acrylate, when the structure excluding R 22 is defined as B-X, the particles have a B-X content of 5.0% by mass or more and 17.5% by mass or less in the particles.

Chemical formula

Chemical formula

[0009] Further, according to the present invention, there is provided an inspection particle characterized in that a ligand is added to the surface of the above particle. Further, according to the present invention, there is provided a reagent in which the above inspection particles are dispersed in an aqueous solution. Further, according to the present invention, there is provided an inspection kit characterized by having the above reagent and a housing containing the above reagent. Further, according to the present invention, there is provided a method for detecting a target substance in a sample, the method being characterized by mixing the above reagent and a sample that may contain the target substance. Further, according to the present invention, there is provided a method for detecting a target substance in a sample by an aggregation method, the method comprising the steps of: mixing the above reagent with a sample that may contain the target substance to obtain a mixed solution; irradiating the mixed solution with light; and detecting at least one of transmitted light and scattered light from the light irradiated on the mixed solution.

Effect of the Invention

[0010] According to the present invention, it is possible to provide particles and inspection particles that improve the redispersibility of particles, particularly the redispersibility in the reactive functional group activation step when a ligand is chemically bonded to the particle surface.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail, but the technical scope of the present invention is not limited to these embodiments.

[0012] <Chemical Structure of Particles According to the Present Invention> The particles according to the present invention are particles containing a copolymer having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (B), wherein when the structure excluding R in the structural unit represented by the formula (B) is B-X, the content of B-X in the particles is 5.0% by mass or more and 17.5% by mass or less. 22 When the structure excluding R in the structural unit represented by the formula (B) is B-X, the particles are particles in which the content of B-X in the particles is 5.0% by mass or more and 17.5% by mass or less.

Chemical Formula

[0013] As a result of intensive studies by the present inventors, it was discovered that it is important that the particles have a structural unit represented by formula (1) having a crosslinked structure and a structural unit represented by formula (B) having a hydrophilic structure, and that the amount of structure (B-X) that expresses the hydrophilicity of the structural unit represented by formula (B) is appropriate. B-X represents the structure obtained by removing R 22 from the structural unit represented by formula (B). The structural unit represented by formula (B) has the effect of imparting hydrophilicity and flexibility to the particles, and the structural unit represented by formula (1) has the effect of imparting hardness to the particles. By superimposing these characteristics and optimizing the amount, a specific improvement in redispersibility can be achieved for the first time. That is, it was found that the particles according to the present invention have a structural unit represented by formula (1) and a structural unit represented by formula (B), and by having 5.0% by mass or more and 17.5% by mass or less of B-X, an improvement in redispersibility is obtained. Particularly, a more remarkable effect was shown in the reactive functional group activation step. The structural unit represented by formula (B), which is a hydrophilic structure, has a crosslinked structure with the structural unit represented by formula (1), and by having a certain content of B-X, it is considered that both the suppression of hydrophobic interaction and the improvement of the hardness of the particles can be achieved simultaneously.

[0014] Just having the structural unit represented by formula (1) does not improve the redispersibility, and also when the content of B-X is reduced within a certain range, no effect of improving the redispersibility was observed. Therefore, the inventors have discovered that the above range is particularly important.

[0015] In the present invention, the copolymer having the structural unit represented by formula (1) and the structural unit represented by formula (B) can have the structural unit represented by formula (1) showing any one of the structures represented by the following formula (L-1), the structure represented by the following formula (L-2), the structure represented by the following formula (L-3), the structure represented by the following formula (L-4), the structure represented by the following formula (L-5), the structure represented by the following formula (L-6), the structure represented by the following formula (L-7), the structure represented by the following formula (L-8), the structure represented by the following formula (L-9), the structure represented by the following formula (L-10), the structure represented by the following formula (L-11), the structure represented by the following formula (L-12), the structure represented by the following formula (L-13), the structure represented by the following formula (L-14), and the structure represented by the following formula (L-15). L may be different for each structural unit.

Chemical formula

[0016] The structural unit represented by formula (1) in the present invention can be any one of the structural units represented by the following formula (1-1), the structural unit represented by the following formula (1-2), the structural unit represented by the following formula (1-3), the structural unit represented by the following formula (1-4), the structural unit represented by the following formula (1-5), the structural unit represented by the following formula (1-6), the structural unit represented by the following formula (1-7), the structural unit represented by the following formula (1-8), the structural unit represented by the following formula (1-9), the structural unit represented by the following formula (1-10), the structural unit represented by the following formula (1-11), the structural unit represented by the following formula (1-12), the structural unit represented by the following formula (1-13), the structural unit represented by the following formula (1-14), and the structural unit represented by the following formula (1-15), but is not limited thereto. Note that the specific structure of the structural unit represented by formula (1) may be different for each structural unit.

[0017]

Chemical formula

Chemical formula

Chemical formula

[0018] Among them, it is preferable that the copolymer having the structural unit represented by formula (1) and the structural unit represented by formula (B) has at least one of the structural unit represented by formula (1-1) and the structural unit represented by formula (1-2) as the structural unit represented by formula (1). This is because, due to the crosslinked structure, the polymer density of the particles can be crosslinked in a low state, and further, by having a branched chain in the crosslinked structure, it is considered that the crystalline structure in the crosslinked structure is reduced. As a result, it is considered that it is possible to prevent a decrease in redispersibility due to the polymer chains being densely packed and entangled with each other, and also to reduce the hydrophobic interaction of the particles due to the reduction of the crystalline structure, leading to an improvement in redispersibility.

[0019] The above structure can be formed by adding a crosslinking agent monomer during production. Specific crosslinking agent monomers include ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 1,3 - butanediol diacrylate, 1,3 - butanediol dimethacrylate, dioxane glycol diacrylate, dioxane glycol dimethacrylate, glycerin 1,3 - diglycerolate diacrylate, glycerin 1,3 - diglycerolate dimethacrylate, methylene bisacrylamide, glycerol diacrylate, glycerol dimethacrylate, dipropylene glycol diacrylate, and dipropylene glycol dimethacrylate, etc., but are not particularly limited as long as the formula (1) is satisfied. Among them, glycerol dimethacrylate and dipropylene glycol diacrylate are preferable because the structural units represented by the formula (1 - 1) and the structural unit represented by the formula (1 - 2) can be obtained respectively.

[0020] In the particles, the content of the structural unit represented by the formula (1) is preferably 1% by mass or more and 10% by mass or less. By having 1% by mass or more, the effect of improving the hardness of the particles can be enhanced, and by making it 10% by mass or less, the effect of suppressing the hydrophobic interaction of the particles can be enhanced.

[0021] In addition, the particles of the present invention have a structural unit represented by the formula (B).

Chemical formula

[0022] The structural unit represented by formula (B) preferably has a hydroxy group or a carboxy group. More preferably, the structural unit represented by formula (B) has both a hydroxy group and a carboxy group at the same time.

[0023] Examples of the structural unit represented by formula (B) include a structural unit represented by the following formula (B-11). [Chemical formula]

[0024] In the present invention, the structural unit represented by formula (B), for example, the structural unit represented by formula (B) having an epoxy group, can be obtained by adding a monomer during the production of the particles. The monomer to be added is not particularly limited, and examples thereof include glycidyl methacrylate and glycidyl acrylate.

[0025] The structural unit represented by formula (B) is preferably a structural unit represented by the following formula (B-1). [Chemical formula] In formula (B-1), R 21 represents a hydrogen atom or a methyl group, and at least one of R 23 and R 24 represents a hydroxy group, and the other represents a hydroxy group, a structure represented by the following formula (B-2), or a structure represented by the following formula (B-3). [Chemical formula] R 25 represents a single bond or a methylene group. R 26 , R 27 , and R 28 each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a hydroxy group, a hydroxymethyl group, a carboxy group, an amino group, or a thiol group. Y 1represents a sulfur atom or an imino group. * represents the bonding position in the structural unit represented by formula (B-1).

Chemical formula

[0026] Examples of the structural unit represented by formula (B-1) having the structure represented by formula (B-2) or the structure represented by formula (B-3) include, but are not limited to, the structural units represented by the following formulas (B-12) to (B-34). The specific structure of the structural unit represented by formula (B) may be different for each structural unit.

[0027]

Chemical formula

Chemical formula

[0028] The structure having a hydroxy group, a carboxy group, an amino group, or a thiol group in formula (B) can be obtained by adding a modifier to the particles into which an epoxy group has been introduced. The modifier to be added is not particularly limited, and examples include mercaptosuccinic acid, aspartic acid, 3-mercapto-1,2-propanediol, 3-amino-1,2-propanediol, 2-amino-1,3-propanediol, ethanolamine, tris(hydroxymethyl)aminomethane, 1,2-ethylenediamine, 1,2-ethanedithiol, and 2-aminoethanethiol.

[0029] In the present invention, it is preferable that the particles further have a structural unit represented by the following formula (A). By having the structural unit represented by formula (A) in the particles, the refractive index of the particles is increased. When the test reagent reacts with and aggregates the target substance, the absorbance increases. However, when particles with a high refractive index aggregate, the absorbance increases even more. Therefore, the difference in absorbance before and after aggregation also becomes larger, improving the sensitivity.

Chemical formula

[0030] In the present invention, the structural unit represented by formula (A) can be formed by adding a monomer during the production of the particles. Specific examples of the monomer include styrenes, 1-vinylnaphthalene, 2-vinylnaphthalene, and particularly styrene is preferred. These monomers may be used alone or a plurality of them may be used simultaneously. Styrenes: styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, m-ethylstyrene, p-ethylstyrene, 4-vinylphenol, 4-vinylbenzoic acid, sodium p-styrenesulfonate, etc.

[0031] In the present invention, when the content of the structural unit represented by the formula (A) in the particles is M(A) and the content of B-X in the particles is M(B), the value of the mass ratio [M(B) / M(A)] is preferably 0.05 or more and 1.00 or less. Further, the value of [M(B) / M(A)] is more preferably 0.05 or more and 0.45 or less. By being 0.05 or more, the hydrophilicity can be improved and the redispersibility can be improved. Further, by making it 1.00 or less, the particles become hard and are less likely to be affected by deformation or the like in the centrifugation and redispersion steps, and the redispersibility can be improved. The particles of the present invention are not particularly limited, but the volume average particle diameter can be 10 nm or more and 1000 nm or less. Further, the value of the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is preferably 1.25 or less. More preferably, the value of Dv / Dn is less than 1.15. It is known that the closer the value of Dv / Dn is to 1, the narrower the particle size distribution becomes. By making the value of Dv / Dn 1.25 or less, the variation in the size of the particles is reduced, and the contact area between the particles is reduced, so that the redispersibility is considered to be improved.

[0032] The particles according to the present invention are particles obtained by a production method including a polymerization step of performing a polymerization reaction of a reaction system containing at least one of glycidyl methacrylate and glycidyl acrylate, a monomer represented by the following formula (G1), and a monomer represented by the following formula (A1). In the polymerization step, the total content of glycidyl methacrylate and glycidyl acrylate with respect to the content of the monomer represented by the following formula (A1) can be 10% by mass or more and 70% by mass or less.

Chemical formula

[0033] In addition, the particles according to the present invention are particles obtained by a production method including a polymerization step of performing a polymerization reaction of a reaction system containing at least one of glycidyl methacrylate and glycidyl acrylate, and a monomer represented by the formula (G1). In the particles, when the structure of the structural unit represented by the formula (B) derived from at least one of glycidyl methacrylate and glycidyl acrylate, excluding R 22 is defined as B-X, the content of B-X in the particles can be 5.0% by mass or more and 17.5% by mass or less. In this case, when the reaction system contains both glycidyl methacrylate and glycidyl acrylate, the structural unit represented by the formula (B) includes both those derived from glycidyl methacrylate and those derived from glycidyl acrylate.

[0034] The content of B-X in the particles and the content of each structural unit can be calculated from the amount of monomers charged in the polymerization step. For example, the mass of the monomer having B-X is calculated with respect to the total mass of all monomers other than the charged solvent, etc., and further the mass of B-X is estimated to calculate the content of B-X. For example, the solution after the polymerization reaction is analyzed using gas chromatography to quantify the remaining monomers, and the value (polymerization conversion rate) indicating to what extent the monomers are polymerized and converted by the polymerization reaction is obtained from the remaining amount of monomers, and the content of B-X etc. can be obtained. In this case, when the remaining amount of monomers is below the detection limit, the polymerization conversion rate can be considered to be substantially 100% (all monomers are polymerized).

[0035] Further, the particles according to the present invention are preferably particles characterized by using a water-soluble polymerization initiator in the above polymerization step. The water-soluble polymerization initiator preferably has an amide structure, an amidine group, or an imidazoline structure. When the particles produced by the above production method are used, particles excellent in redispersibility, particularly, in the case of chemically bonding a ligand to the particle surface, particles and assay particles having improved redispersibility in the reactive functional group activation step can be provided. The method for producing particles will be specifically described below.

[0036] <Method for Producing Particles According to the Present Invention> The method for producing particles according to the present invention includes a polymerization step of performing a polymerization reaction of a reaction system containing at least one of glycidyl methacrylate and glycidyl acrylate, and a monomer represented by formula (G1). In the polymerization step, the reaction system may contain a monomer represented by formula (A1). In the polymerization step, when the reaction system contains a monomer represented by formula (A1), the total content of glycidyl methacrylate and glycidyl acrylate with respect to the content of the monomer represented by formula (A1) can be 10% by mass or more and 70% by mass or less.

[0037] In the polymerization step, glycidyl methacrylate, glycidyl acrylate, and the polymerization initiator may be added partially first to initiate the polymerization reaction, and then the remainder may be added together with the monomer represented by formula (G1) to continue the polymerization reaction. As the method for producing particles, a method of performing soap-free emulsion polymerization in the polymerization step is preferable. By using soap-free emulsion polymerization, the particle size distribution becomes uniform, the sensitivity is stabilized, and the detection limit can be improved in a region where the concentration of the target substance is low. The polymerization initiator used for producing the particles is not particularly limited, but in the polymerization step, it is preferable to add a water-soluble polymerization initiator. Although the details of the mechanism are not clear, it is considered as follows.

[0038] It is assumed that by using a water-soluble polymerization initiator, the reaction points of polymerization can be made on the particle surface. By using a monomer represented by formula (G1) for forming the structural unit represented by formula (1), that is, a crosslinking agent monomer and a water-soluble polymerization initiator in combination, the hardness of the particle surface can be further improved, and thereby the redispersibility is considered to be improved. Specific examples of the water-soluble polymerization initiator include 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] tetrahydrate, 2,2'-azobis(2-methylpropionamidine) dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] disulfate dihydrate, potassium peroxydisulfate, sodium peroxydisulfate, and ammonium peroxydisulfate are preferred.

[0039] The particles in the present invention preferably contain a compound having an amidine group, an amide structure, or an imidazoline structure. In the polymerization step, it is preferable to use a polymerization initiator having an amide structure, an amidine group, or an imidazoline structure, and the particles preferably contain a structure derived from the above polymerization initiator. Among them, it is more preferable that the particles contain a compound having an amidine group. Further, the method for producing the particles may have an addition reaction step of causing an addition reaction to the particles using a modifier having a hydroxy group, a carboxy group or a salt thereof. As the modifier having a hydroxy group, a carboxy group or a salt thereof, the above-described modifier for introducing a structure having a hydroxy group, a carboxy group, an amino group, or a thiol group in the structural unit represented by the formula (B) in the particles can be used. In order to determine whether each of the above structures has been added to the particles, the reaction solution after the addition reaction can be analyzed using high performance liquid chromatography. The remaining modifier can be quantified, and a value (addition reaction conversion rate) indicating the degree of reaction by the addition reaction can be evaluated from these remaining amounts. When the remaining amount of the modifier is below the detection limit, it can be assumed that the addition reaction conversion rate is substantially 100% (all the modifiers have undergone an addition reaction).

[0040] <Inspection method using the particles according to the present invention> The inspection method using the particles in the present embodiment is not particularly limited, but an inspection method using an antibody (antigen) as a ligand and an antigen (antibody) as a target substance is preferable. Specifically, an immunochromatography method, an immunofluorescence analysis method, a chemiluminescent immunoassay method, an agglutination method (so-called latex agglutination method), etc. can be mentioned, and among them, it can be preferably applied to the agglutination method widely used in the fields of clinical inspection, biochemical research, etc.

[0041] In the inspection method in the agglutination method, inspection particles having, for example, an antibody (antigen) added as a ligand to the surface of the particles according to the present invention can be used. At the time of inspection, the above inspection particles can be dispersed in an aqueous solution and used as a reagent. In the method for detecting a target substance in a sample, the above reagent and a sample that may contain the target substance are mixed. The mixing of the reagent containing the inspection particles in the present embodiment and the sample is preferably performed in the range of pH 3.0 to pH 11.0. Further, the mixing temperature is in the range of 20°C to 50°C, and the mixing time is in the range of 1 minute to 20 minutes. Also, it is preferable to use a solvent in this detection method.

[0042] In addition, in the detection method of the present embodiment, the concentration of the test particles in the present embodiment is preferably from 0.001% by mass to 5% by mass, more preferably from 0.01% by mass to 1% by mass in the reaction system. The detection method in the present embodiment preferably optically detects the aggregation reaction resulting from the mixing of the test particles and the sample in the present embodiment, that is, detects the target substance in the sample by the agglutination method. Specifically, it includes a step of mixing a sample that may contain the target substance with a reagent containing test particles to obtain a mixed solution, a step of irradiating the mixed solution with light, and a step of detecting at least one of transmitted light and scattered light from the light irradiated on the mixed solution. By optically detecting the above-mentioned aggregation reaction occurring in the mixed solution, the target substance in the sample can be detected, and furthermore, the concentration of the target substance can also be measured. As a method for optically detecting the aggregation reaction, the change amount of these values may be measured using an optical instrument capable of detecting scattered light intensity, transmitted light intensity, absorbance, etc.

[0043] <In Vitro Diagnostic Test Reagent> The in vitro diagnostic test reagent in the present embodiment, that is, the reagent for detecting the target substance in the sample by in vitro diagnosis, has the test particles in the present embodiment and a dispersion medium for dispersing the test particles. The amount of the test particles according to the present embodiment contained in the reagent in the present embodiment is preferably from 0.001% by mass to 20% by mass, more preferably from 0.01% by mass to 10% by mass. The reagent in the present embodiment may contain a third substance such as a solvent or a blocking agent in addition to the test particles in the present embodiment within the range capable of achieving the object of the present invention. Two or more types of third substances such as a solvent and a blocking agent may be combined and contained. Examples of the dispersion medium used in the present invention include various buffer solutions such as phosphate buffer solution, glycine buffer solution, Good buffer solution, Tris buffer solution, and ammonia buffer solution, but the dispersion medium contained in the reagent in the present embodiment is not limited thereto.

[0044] <Test Kit> The kit for detecting the target substance in the sample by in vitro diagnosis in the present embodiment has the above-mentioned reagent and a housing containing the above-mentioned reagent. As the kit in the present embodiment, in addition to the reagent in the present embodiment, it is preferable to further include a reaction buffer containing albumin. Examples of albumin include serum albumin, etc., and those treated with protease may also be used. The amount of albumin contained in the reaction buffer containing albumin is preferably in the range of 0.001% by mass to 5% by mass, but the kit in the present embodiment is not limited thereto. A sensitizer for the agglutination method may be contained in both or either one of the reagent in the present embodiment and the reaction buffer containing albumin. Examples of the sensitizer for the agglutination method include polyvinyl alcohol, polyvinylpyrrolidone, polyalginic acid, etc., but the present invention is not limited thereto. Further, the kit in the present embodiment may include a positive control, a negative control, a serum diluent, etc. in addition to the reagent in the present embodiment and the reaction buffer containing albumin. As the medium for the positive control and the negative control, in addition to serum and physiological saline that do not contain the target substance that can be measured, a solvent may also be used. The kit in the present embodiment can be used in the method for detecting the target substance according to the present embodiment in the same manner as a kit for detecting the target substance in a specimen by ordinary in vitro diagnosis. Also, the concentration of the target substance can be measured by a conventionally known method, and in particular, it is preferably used for detecting the target substance in a specimen by the agglutination method.

[0045] <Method for manufacturing inspection particles> To manufacture inspection particles, the particles in the present embodiment are redispersed. Examples of the method for redispersing the particles include a redispersion method by stirring and a redispersion method by vibration. Examples of the redispersion method by stirring include a stirring method for forming a vortex such as a vortex mixer and a method for directly stirring the precipitate. Examples of the redispersion method by vibration include an ultrasonic dispersion method. Examples of the dispersion medium include various buffers such as phosphate buffer, glycine buffer, Good buffer, Tris buffer, and ammonia buffer. By adding a ligand to the surface of the particles according to the present invention, it can be used as a test particle for a specific target. When adding the ligand to the surface by a chemical bond, it is necessary to activate the reactive functional groups on the particle surface. That process is defined as the reactive functional group activation process. The method used in the reactive functional group activation process is not particularly limited, and general methods can be used. When the reactive functional group is a carboxy group, it can be activated using a condensing agent and a condensation aid. As the condensing agent, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, N,N'-dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide are preferred. As the condensation aid, 1-hydroxybenzotriazole, sodium N-hydroxysulfosuccinimide are preferred.

[0046] Also, the ligand in the present invention can be defined as a compound that specifically binds to the receptor possessed by a specific target substance. The site where the ligand binds to the target substance is determined and has selective or specifically high affinity. For example, antigen and antibody, enzyme protein and its substrate, signal substances such as hormones and neurotransmitters and their receptors, nucleic acids, etc. are exemplified, but the ligand in the present invention is not limited thereto. Examples of the nucleic acid include deoxyribonucleic acid. The test particles in the present invention have selective or specifically high affinity (affinity) for the target substance. It is preferred that the ligand in the present invention is any one of an antibody, an antigen, and a nucleic acid. As described above, test particles using the particles according to the present invention can be obtained.

Example

[0047] Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0048] [Production Example 1] (Synthesis of Particle 1) The following materials were weighed into a 2 L four-neck separable flask to obtain a mixed solution. · 33.85 g of styrene (St: Kishida Chemical Co., Ltd.) · 0.61 g of divinylbenzene (DVB: Kishida Chemical Co., Ltd.) · 14.79 g of pre-added glycidyl methacrylate (GMA: Kishida Chemical Co., Ltd.) · 1195.00 g of ion-exchanged water Subsequently, while stirring this mixed solution at 100 rpm, it was maintained at 70 °C, and nitrogen flow was carried out at a flow rate of 200 ml / min to deoxygenate the inside of the four-neck separable flask. Next, a solution prepared separately by dissolving 1.67 g of pre-added V-50 (Fuji Film Wako Pure Chemical Industries, Ltd.) in 30.00 g of ion-exchanged water was added to the above mixed solution to initiate soap-free emulsion polymerization. Two hours after the start of polymerization, 2.82 g of post-added GMA and 1.85 g of glycerol dimethacrylate (GDM: manufactured by Tokyo Chemical Industry Co., Ltd.) were added to the radical polymerization reaction field. Further, a solution prepared separately by dissolving 0.06 g of post-added V-50 in 10.00 g of ion-exchanged water was added, and after maintaining at 70 °C while stirring at 100 rpm for 46 hours, it was gradually cooled to room temperature. At this point, the contents of the 2 L flask were sampled and analyzed using gas chromatography. The remaining monomers were quantified, and the value (polymerization conversion rate) indicating the degree to which the monomers were polymerized and converted by the polymerization reaction was evaluated from the remaining monomer amount. As a result, it was confirmed that the remaining monomer amount was below the detection limit and the polymerization conversion rate was substantially 100%. Next, an addition reaction was carried out on the particles. Mercaptosuccinic acid (MSA: Wako Pure Chemical Industries, Ltd.) and 3-mercapto-1,2-propanediol (MPD: Wako Pure Chemical Industries, Ltd.) were previously mixed in a molar equivalent ratio of 1:1 and dissolved to prepare an aqueous solution. This solution was added so that the total molar amount of MSA and MPD was the same as the molar amount of the above GMA, and triethylamine (Kishida Chemical Co., Ltd.) was added to adjust the pH to 10. Next, while stirring the above at 200 rpm, the temperature was raised to 70 °C and maintained in this state for 18 hours to obtain a dispersion of Particle 1. The reaction solution after the addition reaction was analyzed using high performance liquid chromatography. The remaining modifiers (MSA and MPD in Production Example 1) were quantified, and from the remaining amounts of these, the value (addition reaction conversion rate) indicating the degree of reaction by the addition reaction was evaluated. As a result, it was confirmed that the remaining amount of the modifier was below the detection limit and the addition reaction conversion rate was substantially 100%. Particle 1 was separated from the above dispersion using a centrifuge, and the operation of redispersing Particle 1 in ion-exchanged water was repeated 5 times to purify Particle 1, which was finally stored in the state of an aqueous dispersion adjusted to 1.0 mass%. Table 1 shows the results of evaluating the particle physical properties of Particle 1 and the mass ratio of B-X in Particle 1.

[0049] [Production Example 2] (Synthesis of Particle 2) A dispersion of Particle 2 was obtained by the same experimental procedure as in Production Example 1, except that 1.97 g of dipropylene glycol diacrylate (DPGDA: manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 1.85 g of GDM. When the polymerization conversion rate was evaluated using gas chromatography and the addition reaction conversion rate was evaluated using high performance liquid chromatography, it was confirmed that both were substantially 100%. Table 1 shows the results of evaluating the particle physical properties of Particle 2 and the mass ratio of B-X in Particle 2.

[0050] [Production Example 3] (Synthesis of Particle 3) A dispersion of Particle 3 was obtained by the same experimental procedure as in Production Example 1, except that DVB was not added. The polymerization conversion rate was evaluated using gas chromatography, and the addition reaction conversion rate was evaluated using high performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. Table 1 shows the results of evaluating the particle physical properties of Particle 3 and the mass ratio of B-X in Particle 3.

[0051] [Production Example 4] (Synthesis of Particle 4) A dispersion of Particle 4 was obtained by the same experimental procedure as in Production Example 1, except that the amount of pre-added GMA was changed from 14.79 g to 3.13 g, the amount of pre-added V-50 was changed from 1.67 g to 1.27 g, the amount of post-added GMA was changed from 2.82 g to 0.60 g, 1.85 g of GDM was replaced with 1.61 g of ethylene glycol dimethacrylate (EDMA, manufactured by Tokyo Chemical Industry Co., Ltd.), and the amount of post-added V-50 was changed from 0.06 g to 0.01 g. The polymerization conversion rate was evaluated using gas chromatography, and the addition reaction conversion rate was evaluated using high performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. Table 1 shows the results of evaluating the particle physical properties of Particle 4 and the mass ratio of B-X in Particle 4.

[0052] [Production Example 5] (Synthesis of Particle 5) A dispersion of Particle 5 was obtained by the same experimental procedure as in Production Example 1, except that 1.85 g of GDM was replaced with 1.61 g of EDMA. The polymerization conversion rate was evaluated using gas chromatography, and the addition reaction conversion rate was evaluated using high performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. Table 1 shows the results of evaluating the particle physical properties of Particle 5 and the mass ratio of B-X in Particle 5.

[0053] [Production Example 6] (Synthesis of Particle 6) A dispersion of Particle 6 was obtained by the same experimental procedure as in Production Example 5, except that the amount of EDMA was changed from 1.61 g to 6.44 g. The polymerization conversion rate was evaluated by gas chromatography, and the addition reaction conversion rate was evaluated by high performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. Table 1 shows the results of evaluating the particle physical properties of Particle 6 and the mass ratio of B-X in Particle 6.

[0054] [Production Example 7] (Synthesis of Particle 7) A dispersion of Particle 7 was obtained by the same experimental procedure as in Production Example 1, except that the amount of pre-added GMA was changed from 14.79 g to 19.68 g, the amount of pre-added V-50 was changed from 1.67 g to 1.84 g, the amount of post-added GMA was changed from 2.82 g to 3.75 g, 1.61 g of EDMA was used instead of 1.85 g of GDM, and the amount of post-added V-50 was changed from 0.06 g to 0.09 g. The polymerization conversion rate was evaluated by gas chromatography, and the addition reaction conversion rate was evaluated by high performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. Table 1 shows the results of evaluating the particle physical properties of Particle 7 and the mass ratio of B-X in Particle 7.

[0055] [Production Example 8] (Synthesis of Particle 8) A dispersion of Particle 8 was obtained by the same experimental procedure as in Production Example 5, except that the amount of EDMA was changed from 1.61 g to 0.32 g. The polymerization conversion rate was evaluated by gas chromatography, and the addition reaction conversion rate was evaluated by high performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. Table 1 shows the results of evaluating the particle physical properties of Particle 8 and the mass ratio of B-X in Particle 8.

[0056] [Production Example 9] (Synthesis of Particle 9) A dispersion of Particle 9 was obtained by the same experimental procedure as in Production Example 5, except that the amount of EDMA was changed from 1.61 g to 9.66 g. The polymerization conversion rate was evaluated by gas chromatography, and the addition reaction conversion rate was evaluated by high performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. The results of evaluating the particle physical properties of Particle 9 and the mass ratio of B-X in Particle 9 are shown in Table 1.

[0057] [Production Example 10] (Synthesis of Particle 10) A dispersion of Particle 10 was obtained by the same experimental procedure as in Production Example 5, except that the reagents in the addition reaction to the particles were changed from MSA and MPD to MSA and 3-amino-1,2-propanediol (APD: manufactured by Tokyo Chemical Industry Co., Ltd.). The polymerization conversion rate was evaluated using gas chromatography, and the addition reaction conversion rate was evaluated using high-performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. The results of evaluating the particle physical properties of Particle 10 and the mass ratio of B-X in Particle 10 are shown in Table 1.

[0058] [Comparative Production Example 1] (Synthesis of Comparative Particle 1) A dispersion of Comparative Particle 1 was obtained by the same experimental procedure as in Production Example 5, except that the pre-added GMA was changed from 14.79 g to 22.75 g, the pre-added V-50 was changed from 1.67 g to 1.94 g, the post-added GMA was changed from 2.82 g to 4.33 g, and the post-added V-50 was changed from 0.06 g to 0.10 g. The polymerization conversion rate was evaluated using gas chromatography, and the addition reaction conversion rate was evaluated using high-performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. The results of evaluating the particle physical properties of Comparative Particle 1 and the mass ratio of B-X in Comparative Particle 1 are shown in Table 1.

[0059] [Comparative Production Example 2] (Synthesis of Comparative Particle 2) A dispersion of Comparative Particle 2 was obtained by the same experimental procedure as in Production Example 5, except that the pre-added GMA was changed from 14.79 g to 2.27 g, the pre-added V-50 was changed from 1.67 g to 1.25 g, the post-added GMA was changed from 2.82 g to 0.43 g, and the post-added V-50 was changed from 0.06 g to 0.01 g. The polymerization conversion rate was evaluated using gas chromatography, and the addition reaction conversion rate was evaluated using high-performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. The results of evaluating the particle physical properties of Comparative Particle 2 and the mass ratio of Formula B-X in Comparative Particle 2 are shown in Table 1.

[0060] [Comparative Production Example 3] Synthesis of Comparative Particle 3 A dispersion of Comparative Particle 3 was obtained by the same experimental procedure as in Production Example 5, except that the amount of GMA added first was changed from 14.79 g to 54.02 g, the amount of V-50 added first was changed from 1.67 g to 3.00 g, the amount of GMA added later was changed from 2.82 g to 10.29 g, and the amount of V-50 added later was changed from 0.06 g to 0.23 g. The polymerization conversion rate was evaluated using gas chromatography, and the addition reaction conversion rate was evaluated using high-performance liquid chromatography. As a result, it was confirmed that both were substantially 100%. Table 1 shows the results of evaluating the particle physical properties of Comparative Particle 3 and the mass ratio of B-X in Comparative Particle 3.

[0061] [Comparative Production Example 4] Synthesis of Comparative Particle 4 1195.00 g of ion-exchanged water and 0.23 g of an organic solvent (Shellzol TK, manufactured by Shell Chemicals) were weighed into a 2 L four-neck separable flask to obtain a mixed solution. Then, while stirring this mixed solution at 100 rpm, it was maintained at 70 °C, and nitrogen flow was performed at a flow rate of 200 ml / min to deoxygenate the inside of the four-neck separable flask. Next, a separately prepared mixed solution of 33.85 g of St, 0.61 g of DVB, 27.08 g of GMA, and 1.67 g of azobisisobutyronitrile (AIBN, manufactured by Fujifilm Wako Pure Chemical Corporation) was added to the above mixed solution to initiate emulsion polymerization. After maintaining at 70 °C while stirring at 100 rpm for 46 hours, it was gradually cooled to room temperature. At this point, the contents of the 2 L flask were sampled, and the radical polymerization conversion rate was evaluated using gas chromatography. As a result, it was confirmed that it was substantially 100%. Next, the addition reaction to the particles was carried out in the same manner as in Production Example 1. Table 1 shows the results of evaluating the particle physical properties of Comparative Particle 4 and the mass ratio of formula (B-X) in Comparative Particle 4.

[0062]

Table 1

[0063] [Evaluation 1] Evaluation of the Redispersibility of Activated Particles (Reactive Functional Group Activation Step of Particles) For the particles prepared in Production Examples 1 to 10 and Comparative Production Examples 1 to 4, 180 μL of a 1.7% by mass water suspension was respectively placed in a 1.5 mL microtube. The following materials were added thereto. · 90 μL of a 5.0% aqueous solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride as a condensing agent · 90 μL of a 5.0% aqueous solution of N-hydroxysulfosuccinimide sodium as a condensation aid Particles activated by stirring at room temperature for 30 minutes (hereinafter referred to as activated particles) were obtained.

[0064] (Redispersibility Evaluation) The dispersion of the activated particles prepared above was sedimented by a centrifuge at a force of 20000G for 5 minutes, the supernatant was removed, and 250 μL of a Tris-HCl buffer solution with a pH of 8.0 was newly added. Six samples of the activated particle precipitate with the buffer solution added were prepared, and ultrasonic dispersion treatment was carried out 16 seconds × 20 times at a mode of High and a liquid temperature of 4 °C using an ultrasonic disruptor Bioruptor II (TYPE6) manufactured by Sonic Bio Co., Ltd. After visually confirming the state of the particles in the microtube after the ultrasonic dispersion treatment, the particle size of each particle was measured with a Zetasizer ULTRA manufactured by Spectris Co., Ltd., and the average value of the six samples of the particle size change before and after activation was calculated and evaluated as follows. A: Activated particle size after ultrasonic dispersion / Particle size before activation = 1.05 or less B: Activated particle size after ultrasonic dispersion / Particle size before activation > 1.05 and ≤ 1.1 C: Activated particle size after ultrasonic dispersion / Particle size before activation > 1.1 and ≤ 1.5 D: Activated particle size after ultrasonic dispersion / Particle size before activation > 1.5 and ≤ 2.0 E: Sediment remained visually The evaluation results of the activated particles of Particles 1 to 10 and Comparative Particles 1 to 4 are shown in Table 2.

[0065]

Table 2

[0066] [Evaluation 2] Evaluation of non-specific adsorption to particles (Milk turbidity evaluation) For Particle 1, a dispersion was prepared by dispersing it in a phosphate buffer so as to be 0.1% by mass. Next, 60 μl of a milk turbidity solution composed of triolein, lecithin, free fatty acid, bovine albumin, and Tris buffer was added to 30 μl of the above dispersion, and the absorbance at a wavelength of 572 nm was measured for the dispersion immediately after stirring. The absorbance measurement was performed using a spectrophotometer Biospectrometer manufactured by Eppendorf. Then, after allowing these dispersions to stand at 37 °C for 5 minutes, the absorbance at a wavelength of 572 nm was measured again, and the change amount of absorbance ΔABS×10000 was calculated. The evaluation was made as follows according to the value of ΔABS×10000. AA: ΔABS×10000 is 30 or less A: ΔABS×10000 is greater than 30 and 50 or less B: ΔABS×10000 is greater than 50 and 100 or less C: ΔABS×10000 is greater than 100 and 500 or less D: ΔABS×10000 is greater than 500 The evaluation result was AA. It was confirmed that the particles of the present invention are excellent in the ability to suppress non-specific adsorption.

[0067] [Evaluation 3] Preparation of test particles by antibody sensitization to particles and evaluation of the aggregation sensitivity of the test particles (Preparation of test particles by antibody sensitization to particles) For Particle 1, 180 μL of a 1.7% by mass water-suspension was taken into a 1.5 mL microtube. 90 μL of a 5.0% aqueous solution of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 90 μL of a 5.0% aqueous solution of N-hydroxysulfosuccinimide sodium were added, and the mixture was stirred at room temperature for 30 minutes to obtain an activated particle dispersion (activated particle dispersion). After centrifugal washing, 270 μL of a phosphate buffer - physiological saline solution (hereinafter referred to as PBS) with a pH of 7.2 was added, and the activated particles were dispersed by ultrasonic waves. To this, 5 μL of a 4.9 mg / mL dispersion of monoclonal mouse anti-human C-reactive protein (hereinafter referred to as CRP antibody), clone C5 (Funakoshi Corporation), was added, and the mixture was stirred at room temperature for 3 hours to obtain test particles by sensitizing the particles with the antibody. After centrifugal washing of these test particles, 1 mL of PBS was added and stored in a dispersed state.

[0068] (Evaluation of Aggregation Sensitivity of Test Particles) A standard serum for CRP was diluted with PBS to a concentration of 0.75 mg / dL to obtain a CRP specimen solution. A mixture (hereinafter referred to as mixture 1) was prepared by mixing 1 μL of the above CRP specimen solution and 50 μL of a buffer solution (PBS containing 0.01% Tween 20), and the mixture was incubated at 37°C. Next, 50 μL of a dispersion of the above test particles that had been sufficiently dispersed by ultrasonic waves again before use (particle concentration 0.1 mass%) was mixed with mixture 1. The absorbance at a wavelength of 572 nm was measured for the mixture (volume 101 μL) immediately after stirring. The absorbance measurement was performed using a spectrophotometer Biospectrometer manufactured by Eppendorf. Then, after allowing this mixture to stand at 37°C for 5 minutes, the absorbance at a wavelength of 572 nm was measured again, and the value of the change in absorbance ΔABS × 10000 was calculated. As a result of the calculation, a value of 10000 or more was obtained, and the evaluation result was good. It was confirmed that the particles of the present invention have sufficient ability as test particles.

[0069] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) Particles containing a copolymer having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (B), When the structure excluding R of the structural unit represented by the formula (B) is designated as B-X, particles in which the content of B-X in the particles is 5.0 mass% or more and 17.5 mass% or less. 22 [Chemical formula] (In formula (1), L represents an unsubstituted or substituted divalent to hexavalent hydrocarbon group having 1 to 15 carbon atoms which may have an oxy group. R 11 represents a hydrogen atom or a methyl group, and R 12 represents an oxygen atom or an imino group. R 11 , R 12 , and L may be different for each structural unit.) [Chemical formula] (In formula (B), R 21 represents a hydrogen atom or a methyl group, and R 22 represents a group having an epoxy group, a group having a hydroxy group, or a group having a carboxy group or a salt thereof. R 21 and R 22 may be different for each structural unit.) (Constitution 2) The particle according to Constitution 1, further having a structural unit represented by the following formula (A). [Chemical formula] (R 31 represents a hydrogen atom or a methyl group. R 32 represents a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group. Examples of the substituent include a methyl group, an ethyl group, a hydroxy group, a carboxy group or a salt thereof, or a sulfo group or a salt thereof. R 31 and R 32 may be different for each structural unit.) (Constitution 3) The particle according to Constitution 2, wherein when the content of the structural unit represented by the formula (A) in the particle is M(A) and the content of B-X in the particle is M(B), the value of M(B) / M(A) which is the mass ratio is 0.05 or more and 1.00 or less. (Constitution 4) The copolymer has a structural unit represented by the formula (1) in which L represents any one of the structures represented by the following formula (L-1), the structure represented by the following formula (L-2), the structure represented by the following formula (L-3), the structure represented by the following formula (L-4), the structure represented by the following formula (L-5), the structure represented by the following formula (L-6), the structure represented by the following formula (L-7), the structure represented by the following formula (L-8), the structure represented by the following formula (L-9), the structure represented by the following formula (L-10), the structure represented by the following formula (L-11), the structure represented by the following formula (L-12), the structure represented by the following formula (L-13), the structure represented by the following formula (L-14), and the structure represented by the following formula (L-15), and the particles according to any one of Configurations 1 to 3.

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Claims

1. Particles containing a copolymer having a structural unit represented by the following formula (1) and a structural unit represented by the following formula (B), R of the structural unit represented by the formula (B) ２２ When the structure excluding ２２ is defined as B-X, particles in which the content of B-X in the particles is 5.0% by mass or more and 17.5% by mass or less. 【Chemical 1】 (In formula (1), L represents an unsubstituted or substituted divalent to hexavalent hydrocarbon group having 1 or more and 15 or less carbon atoms which may have an oxy group. R １１ represents a hydrogen atom or a methyl group, and R １２ represents an oxygen atom or an imino group. R １１ 、 R １２ 、 and L may be different for each structural unit.) [Chemical Formula 2] (In formula (B), R ２１ represents a hydrogen atom or a methyl group, and R ２２ represents a group having an epoxy group, a group having a hydroxy group, or a group having a carboxy group or a salt thereof. R ２１ and R ２２ may be different for each structural unit.)

2. The particles according to claim 1, further having a structural unit represented by the following formula (A). 【Chemical Formula 3】 (R ３１ represents a hydrogen atom or a methyl group. R ３２ represents a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group. Examples of the substituent include a methyl group, an ethyl group, a hydroxy group, a carboxy group or a salt thereof, or a sulfo group or a salt thereof. R ３１ and R ３２ may be different for each structural unit.)

3. When the content of the structural unit represented by the formula (A) in the particles is M(A) and the content of B-X in the particles is M(B), the value of M(B) / M(A) which is the mass ratio is 0.05 or more and 1.00 or less. The particles according to claim 2.

4. The copolymer has a structural unit represented by the formula (1) in which L represents any one of the structures represented by the following formula (L-1), the structure represented by the following formula (L-2), the structure represented by the following formula (L-3), the structure represented by the following formula (L-4), the structure represented by the following formula (L-5), the structure represented by the following formula (L-6), the structure represented by the following formula (L-7), the structure represented by the following formula (L-8), the structure represented by the following formula (L-9), the structure represented by the following formula (L-10), the structure represented by the following formula (L-11), the structure represented by the following formula (L-12), the structure represented by the following formula (L-13), the structure represented by the following formula (L-14), and the structure represented by the following formula (L-15). The particles according to claim 1. 【Chemical Formula 4】 (* indicates the bonding position with R in formula (1). １２ )

5. The particles according to claim 1, wherein the copolymer has at least one of the structural unit represented by the following formula (1-1) and the structural unit represented by the following formula (1-2) as the structural unit represented by the formula (1). [Chemical Formula 5] [Chemical Formula 6]

6. The particles according to claim 1, wherein the content of the structural unit represented by the formula (1) in the particles is 1% by mass or more and 10% by mass or less.

7. The particles according to claim 1, having a compound having an amide structure, an amidine group or an imidazoline structure.

8. Particles obtained by a production method including a polymerization step of performing a polymerization reaction of a reaction system containing at least one of glycidyl methacrylate and glycidyl acrylate, a monomer represented by the following formula (G1), and a monomer represented by the following formula (A1), In the polymerization step, the total content of glycidyl methacrylate and glycidyl acrylate with respect to the content of the monomer represented by the following formula (A1) is 10% by mass or more and 70% by mass or less. 【Chemical Formula 7】 (In formula (G1), L represents an unsubstituted or substituted hydrocarbon group having 1 to 15 carbon atoms which may have an oxy group.) n represents an integer of 2 or more and 6 or less. R １１ represents a hydrogen atom or a methyl group, and R １２ represents an oxygen atom or an imino group.) 【Chemical Formula 8】 (R ３１ represents a hydrogen atom or a methyl group. R ３２ represents a substituted or unsubstituted phenyl group, or a substituted or unsubstituted naphthyl group. Examples of the substituent include a methyl group, an ethyl group, a hydroxy group, a carboxy group or a salt thereof, or a sulfo group or a salt thereof.)

9. Particles obtained by a production method including a polymerization step of performing a polymerization reaction of a reaction system containing at least one of glycidyl methacrylate and glycidyl acrylate, and a monomer represented by the following formula (G1), In the particle, for the structural unit represented by the following formula (B) derived from at least one of glycidyl methacrylate and glycidyl acrylate, R ２２ When the structure excluding is defined as B-X, a particle in which the content of B-X in the particle is 5.0% by mass or more and 17.5% by mass or less. 【Chemical Formula 9】 (In formula (G1), L represents an unsubstituted or substituted hydrocarbon group having 1 to 15 carbon atoms which may have an oxy group.) n represents an integer of 2 or more and 6 or less. R １１ represents a hydrogen atom or a methyl group, and R １２ represents an oxygen atom or an imino group.) 【Chemical Formula 10】 (In formula (B), R ２１ represents a hydrogen atom or a methyl group, and R ２２ represents a group having an epoxy group, a group having a hydroxy group, or a group having a carboxy group or a salt thereof. R ２１ and R ２２ may be different for each structural unit.)

10. The particles according to claim 8 or 9, wherein in the polymerization step, a water-soluble polymerization initiator is used.

11. The particles according to claim 10, wherein the water-soluble polymerization initiator has an amide structure, an amidine group or an imidazoline structure.

12. Inspection particles, characterized in that a ligand is added to the surface of the particles according to claim 1.

13. A reagent in which the inspection particles according to claim 12 are dispersed in an aqueous solution.

14. An inspection kit, characterized by having the reagent according to claim 13 and a housing enclosing the reagent.

15. A method for detecting a target substance in a sample, characterized by mixing the reagent according to claim 13 and a sample that may contain the target substance.

16. A method for detecting a target substance in a sample by an agglutination method, comprising: a step of mixing a sample that may contain the target substance with the reagent according to claim 13 to obtain a mixture; a step of irradiating the mixture with light; and a step of detecting at least one of transmitted light and scattered light from the light irradiated to the mixture.

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